The present invention relates generally to shoe insoles, and more particularly, to insoles particularly adapted to provide improved proprioception.
The assignee of the present application presently sells insoles under the trademarks “STEPWELL” which molds to the bottom of the foot to relieve high-pressure points and promote healthier foot circulation.
Specifically, these insoles, which are described in applicant's U.S. Pat. No. 6,481,120, the entire disclosure of which is incorporated herein by reference, includes a forefoot portion formed by dual layers of the same outer dimensions and of the same thickness. The dual layers of the forefoot portion are made from different polyurethane foam materials, having different characteristics. Specifically, the bottom layer is made from a resilient foam material that provides a conventional cushioning function. In effect, the bottom layer is a typical foam mechanical spring, shock absorption layer that cushions the foot, in order to decrease pressure in any area of the forefoot. On the other hand, the top layer is made from a slow recovery foam material that has a conforming property. Thus, the top layer temporarily collapses under pressure, and absorbs the shear, that is, dampens the same, and accommodates the shape of the foot. If there are bony protuberances, the top layer absorbs and redistributes the forces. The top layer thereby sculptures to the pressure points and spreads the pressure out along the entire forefoot portion. Thus, by tuning the different layers of the forefoot portion, the forefoot portion optimally accommodates the deformation of the forefoot region of the foot, and reduces foot plantar pressure.
The basis for this construction is that arthritic people commonly experience forefoot pain and swelling in the metatarsal area. This results from a remodeling of the foot, that is, a structural change in the forefoot. Specifically, depressed or prominent metatarsal heads are formed, which result in bony protuberances, and thereby pressure points, at the bottom of the foot, which can be very painful. This causes impaired ambulatory ability and gait. Further, deformation of foot joints in arthritic people can produce excessive plantar pressure, which will worsen the pain and discomfort in the foot. Arthritic people also experience mid-foot/arch problems. By using the two layers, there is a cushioning effect from the lower layer and a pressure redistribution effect from the upper layer, in order to alleviate these problems.
These insoles also include a contoured construction in the medial arch area. The medial arch portion is built up in height and provides spaced apart, transverse oriented grooves or recesses therein, which define transverse flex members between the recesses, the flex members effectively functioning as springs. The flex members function to provide even cushioning support and shock absorption over the entire mid-foot area during mid-stance phase.
Although this construction functions to reduce lower extremity, back and foot pain by optimally accommodating deformation of the forefoot region and reducing foot plantar pressure in the forefoot region, it does not customize in shape to the person's foot to provide maximum proprioception.